The dyslexic person is an idiot. The other people only agreed with him because they are his friend, not because he's right. I think the gamertag was witty, and rolls off the tongue nicely. It's better than all the Optic_Rag3_69 gamertags out there.
Should he rightfully have to change his gamertag? No, of course not. Should he? Yes. Life isn't fair, and you should want to be liked, for better or for worse. It's like when you're growing up and you're told to be who you are and don't try to change yourself to try to fit in. If you don't try to fit in, you end up wearing neon green short shorts and frilly pirate shirts. People want to naturally change themselves to fit in and be liked. Some individuality is nice, but if it negatively affects your life in a major way like making your peers want to hurt you, it would be best to change yourself to be liked. It's sad, but it's true.
Gamertags should be witty and interesting. I mean, when I first created a xbox live account, I used the gamertag Jiggly Breasts since I played Halo 3 a lot. I thought it would be funny to have the kill feed read "Jiggly Breasts beat you down" or "You Splattered Jiggly Breasts". Sadly, eventually I guess I was reported and was forced to change my gamertag to something else. It was probably from one of the many nerds that thought I was a chick and tried flirting with me. I guess telling them I had a penis had its consequences.